ETYM Old Eng. legioun, Old Fren. legion, French légion, from Latin legio, from legere to gather, collect. Related to Legend.
1. A large military unit.
2. Association of ex-servicemen.
Roman army unit. In the later republic and the empire a legion comprised 5,000–6,000 men, mainly foot soldiers, organized in centuries (units of 60–100). Legions were designated by numbers and honorary titles, and served as garrisons or armies in the field. Under the empire there were 25–30 legions, with soldiers serving about 25 years before their discharge with a pension.